Ministerial Approval
In Marin and San Francisco, ADUs and SB 9 projects are approved against written, objective standards, with no hearing and no required design changes. On the right project, that opens up the full zoning allowance for the house you want, on a much quicker timeframe.
Ministerial approval in Marin and San Francisco
Ministerial approval means the city staff checks your application against written, objective standards and approves it when they are met. There is no design review board, no public hearing and no neighbor comments. The building code and the zoning standards written for the pathway still apply in full. What goes away is a board's judgment on the design, so a house that meets the standards is approved as you designed it.
Which path a project takes makes a real difference to how much house can be approved. On a lot zoned for 6,000 square feet, the design review path might realistically approve around 3,500, because hillside guidelines, view corridors and neighbor comments each have effects on the board or commission's final judgment. On the ministerial path, there is no board or commission judgment to place restrictions on the home size. The same lot can reach 6,800 square feet of floor area. Here the full zoning allowance of 6,000 square feet is available, plus state law allows for additional floor area outside the maximum.
Design review can still be the right path for some projects, depending on your project goals. The approval strategy page sets the two side by side.
Three ways onto the ministerial path
For a single-family property there are three common ways in. Some parcels have more than one, and that is where it gets interesting.
1 · An ADU
An accessory dwelling unit is approved ministerially under state law. Up to 800 square feet of it is not counted towards the floor area maximum on the property, and setbacks can be as tight as 4 feet where standard zoning here asks for 5 to 15 feet. It can be detached, attached, or made from space you already have. An existing room with a small kitchenette added can qualify.
In practice the ADU is often multi-functional. The space can become a studio, an office or guest quarters for as long as you like, and the floor area it frees can go into the main house, where you wanted it in the first place.
2 · An SB 9 second unit
SB 9 allows two units on a single-family lot, approved ministerially, and in combination with SB 450, a complete application gets a decision within 60 days. The second unit can be modest or the same size as the main house. It can be a great income-earning rental, or it can become an office, a studio, guest quarters or a wing for adult children or aging parents.
A qualifying SB 9 unit can bring the whole project onto the ministerial path, main house included, not only the unit itself. That opens up far more options for a project that conforms to the zoning district allowances, and far more flexibility in how you develop the site. On a recent Sausalito project, the city agreed in writing.
3 · An SB 9 lot split
SB 9 also allows a single-family lot to be split in two, with two units on each lot. On a larger lot, the split is often where most of the value sits.
Here the order of the steps is worth planning with care. Some options are open only before a lot is designated under SB 9, and the existing houses are easier to change before a split than after. In the right order, you keep every option and get to use each one. In some instances, sequencing can open up far more opportunities.
Does your property qualify?
It depends on the zoning, what already stands on the lot, and historic mapping. SB 9 leaves out parcels in historic districts and certain other zones without the required mitigations, and puts restrictions on some parcels with recent tenancy history. Coastal properties still answer to the Coastal Act. Even where SB 9 is not an option, an ADU can be. A parcel review gives you the answer quickly, and it is where I start.
Ministerial approvals in practice
Below are three projects. In each, the ministerial path was selected as the best strategy to achieve the project goals. Each one used it in a unique way to achieve different goals.
SB 9 · Sausalito Boulevard
My clients owned a highly restricted property and wanted to add a second unit so they could age in place, both physically and financially. Utilizing the SB 9 ministerial path was the only way to get around the property restrictions. Neither the city zoning ordinance nor the ADU laws would allow them to add a second unit. Any proposed structure would not meet the parking and height restrictions set by these rules. By employing the SB 9 path, we were able to avoid these restrictions and receive approval for a new unit. All done ministerially, without design review, on a property that was tiny and already well over on all zoning limits. Now my clients can comfortably remain in their home of 30 years.
ADU · A Sausalito remodel
The house was already at its floor area maximum, and the owners wanted two additions off the primary bedroom to capture the best of the city and bay views. Typically this would have needed a variance, and gaining a variance would be unlikely in this situation. By understanding the nuances of state law and the local zoning ordinance, we added a small kitchenette to an existing space and created an ADU. ADU floor area is discounted from the floor area maximum. This freed up 250 square feet, which we added to the primary bedroom and bathroom, so now both have fabulous city and bay views. All this with no design review.
Lot split · A Mill Valley lot
My client had three days to decide on a 17,000 square foot lot with two 1950s houses. As a single lot, the zoning allows 5,000 square feet of floor area. With the steps in the right order and an SB 9 split among them, we found a way to develop it as two lots, with up to 7,500 square feet and up to four units. That is a 50 percent increase in floor area and two sellable lots instead of one. My client had a clear answer within the three days and went ahead with the purchase.
The ministerial path can get you precisely the home you want, and even more of it.
The ministerial approval process
What are the goals for your property?
It starts with you: what you want the house to be, how you want to live, what you hope to add, and who a second unit would be for, whether family, work, guests or rental income. I listen first. This is what I am working to get you, all the way through approval.
01
Property and code review
With the goals in mind, I read the parcel, state law and the local zoning ordinance language together. Where state law has moved ahead of the local code, that is usually where the extra room is.
02
Approval path and sequence
This usually comes down to two or three viable paths, each with different benefits. Here we can see what each one yields in square feet, site layout and what the approval process will look like. On certain properties the order of the applications can be worth more than any single path. This may lengthen the approval process, but it can increase the value of what can be approved. These are the opportunities my clients get to choose from.
03
The case for approval
For planning staff, I lay out the state law, the local ordinance and the code sections in clear order, demonstrating the project's compliance. Where a reading needs legal weight, a land use attorney I work with adds it. This well-articulated process carries the project to approval.
04
Once the project is approved, the same approach carries into the design, the construction drawings and the build. See how a full project runs →
Meet Scott Couture
Scott has spent 25+ years getting projects approved in San Francisco and Marin, and has been reading California's housing laws against real parcels since they took effect. The new laws and the local codes do not always line up yet. Reading them closely enough to get a client more from a property is his favorite part of the work.
Both approval paths stay live in the practice, so his advice on which path to take follows the project goals. As a licensed architect and contractor, he designs to the written standards with the build cost in view.
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Find out what your property can build
Send me the address and what you have in mind. You will get a read on whether an ADU or SB 9 applies, roughly what the ministerial path would yield in floor area, and which path best fits your project goals. It is a good first step before you buy, and most owners find the property can do more than they expected.
Request a consultation with Scott.
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frequently asked questions
Mostly, you know where you stand. The standards are written down before anything is designed, and a complete ADU or SB 9 application gets a decision within 60 days. There are no subjective restrictions on home size, architectural style, color, window location or window amounts, and no required changes from a board. I wrote a longer explanation of how ministerial approval works in California.
SB 450 took effect in January 2025. A complete SB 9 application now gets a decision within 60 days, some of the tools cities had used to limit SB 9 projects were removed, and the rules apply the same way across California, including charter cities.
No, and it is worth checking before you get attached to an idea. Parcels in historic districts and certain other zones without the required mitigations sit outside it, parcels with recent tenancy history face some restrictions, and coastal properties still answer to the Coastal Act. A thorough parcel review settles it quickly.
It is the most widely available of the three ways in. Under state law, up to 800 square feet of an ADU is not counted towards the floor area maximum on the property, and setbacks drop to 4 feet. An ADU can also be the step that frees floor area for the main house, as it did on the Sausalito remodel above.
Those answers tend to be close and incomplete at the same time. One client arrived with a well-rounded picture that still missed several points that decided the outcome on their property. The statutes are recent, they interact with local ordinances that have not caught up, and the right reading shifts with what already stands on your lot.
When it better serves the project goals: when the parcel does not qualify for a ministerial path, when a project needs a variance, and for some difficult sites that need more latitude than written objective standards allow. Plenty of the best houses around here still go that way. The design review page covers how I prepare for it.
